There has been disclosed a technology relating to an electronic certificate of an x509 format that is used in communication such as SSL (Secure Socket Layer), TLS (Transport Layer Security) and the like. In particular, Patent Document 1 discloses a client apparatus that makes out a certificate signing request (CSR) including an extended area (hereinafter referred to as “extensions”) in accordance with version 3 of the x509 format. A certificate authority makes out the electronic certificate including the extensions based on the certificate signing request prepared by the client apparatus.